The karyotype of Sophora tetraptera (Fabaceae)

Abstract

The karyotype of Sophora tetraptera (Fabaceae (Leguminosae), subfam. Papilionoideae) is reported for the first time. The chromosome number, 2n = 18, coincides with former reports and is the most common number for the genus. The chromosomes are small (average length 1.65 (Am). The karyotype is composed of 8 m (metacentric) + 1 sm (submetacentric) pairs. Microsatellites were observed on the short arm of the only sm pair. The intrachromosomal and interchromosomal asymmetry indices were A1 = 0.16 and A2 = 0.12, respectively. The nine species of Sophora analysed karyotypically so far in the literature suggest that karyotypic features are useful. The diversification of the group apparently has been accompanied by some chromosomal rearrangements yielding differences in karyotype formula and secondary constrictions. Thus, karyotypic data in Sophora are useful for elucidating its taxonomy and evolution.